mission
覜 centers on a formal visit or inspection, often with a sense of looking over or surveying, which aligns with its core meaning of a mission.
覜 combines 兆 (portent, sign) with 見 (see), suggesting the idea of observing signs or inspecting, which fits the mission sense. The exact historical development is uncertain.
The left side 兆 looks like a sign or omen, and the right side 見 is an eye. Imagine a mission where you must go and see the signs for yourself.
For チョウ, picture a mission leader named Chou inspecting the signs: Chou -> チョウ, and he sees everything with his eye 見.